River Blackfish, Gadopsis marmoratus Richardson 1848

Other Names: Blackfish, Duat, Freshwater Blackfish, Marble Cod, Marbled River Cod, Slimy, Slippery, Tasmanian Blackfish

A River Blackfish, Gadopsis marmoratus, from Blackfish Creek Refuge Cove, Wilsons Promontory, Victoria. Source: Ken Harris. License: CC by Attribution-NonCommercial

The River Blackfish is slender with rounded fins, a large head with a rounded snout that slightly overhangs the large mouth, and pelvic fins with a single ray positioned below the gill openings. 

River Blackfish are highly variable in colour, including mottled yellowish, brownish-green, dark brown or greyish with irregular blotches on the upper sides. The lower part of the body ranges from pale bluish-brown, to yellow or purple. The body is covered in very small scales and usually covered in a heavy coat of slime.

Genetic studies indicate that Gadopsis marmoratus is a complex of several cryptic species (Unmack et al. 2017).

Cite this page as:
Bray, D.J. 2019, Gadopsis marmoratus in Fishes of Australia, accessed 29 May 2024, https://fishesofaustralia.net.au/home/species/3877

River Blackfish, Gadopsis marmoratus Richardson 1848

More Info


Endemic to temperate freshwaters of south-eastern Australia, and found in west-flowing streams in New South Wales and southern Queensland as far as the Condamine River; in the north only at altitudes above 600–900 m, in the south, found west and as low as 150 m elevation. In Victoria, the species occurs in tributaries of the Murray system and in south-flowing streams; absent from many smaller coastal streams, such as those in Otway Ranges.

River Blackfish occur in a range of habitats from clear flowing streams with rock cover, snags and woody debris, to slow-flowing lowland rivers, lakes and reservoirs. 


River Blackfish are ambush predators, feeding on fishes, crustaceans and aquatic insects.


The species breeds in late spring to early summer, and females lays large, adhesive eggs in submerged hollow logs, snags and amongst boulders. Males guard the eggs and newly hatched larvae. After hatching, the larvae remain tethered to the egg case until they have used up their yolk sac and are ready to commence feeding by mouth. This adaptation presumably prevents the larvae being washed downstream by the currents.


A popular angling fish in parts of its range, reportedly with sweet-tasting flesh.


Populations of River Blackfish  have been affected by increased siltation on streams, desnagging of rivers, changed stream flows from the construction of dams and weirs, and competition from introduced species such as trout. The species is protected in South Australia.


The name "Duat" is the Woiwurrung word for this species. The Woiwurrung is the language spoken by the Wurundjeri people of the Kulin Nation of Central Victoria.

Species Citation

Gadopsis marmoratus Richardson 1848, Zool. Voy. Erebus and Terror:  122. Type locality: Murray River, South Australia.


Bray, D.J. 2019


Atlas of Living Australia

River Blackfish, Gadopsis marmoratus Richardson 1848


Allen, G.R. 1989. Freshwater Fishes of Australia. Neptune, New Jersey : T.F.H. Publications 240 pp., 63 pls.

Allen, G.R., Midgley, S.H. & Allen, M. 2002. Field Guide to the Freshwater Fishes of Australia. Perth : Western Australian Museum 394 pp.

Cadwallader, P.L. & Backhouse, G.N. 1983. A Guide to the Freshwater Fish of Victoria. Melbourne : F.D. Atkinson Government Printer 249 pp. figs.

Chilcott, S. J. & Humphries, P. 1996. Freshwater fish of northeast Tasmania with notes on the dwarf galaxias. Records of the Queen Victoria Museum, Launceston 103: 145-149.

Davies, P.E. 1989. Relationships between habitat characteristics and population abundance for Brown Trout, Salmo trutta L., and Blackfish, Gadopsis marmoratus Rich., in Tasmanian streams. Australian Journal of Marine and Freshwater Research 40: 341-359.

Hammer, M.P. & Walker, K.F. 2004. A catalogue of South Australian freshwater fishes, including new records, range extensions and translocations. Transactions of the Royal Society of South Australia 128(2): 85-97.

Hammer, M.P., Unmack, P.J., Adams, M., Raadik, T.A., Johnson, J.B. 2014. A multigene molecular assessment of cryptic biodiversity in the iconic freshwater blackfishes (Teleostei: Percichthyidae: Gadopsis) of southeastern Australia. Biological Journal of the Linnean Society 111: 521–540.

Huey, J.A, Balcombe, S.R., Real, K.M. & Hughes, J. 2017. Genetic structure and effective populations size of the most northern population of the Australian River Blackfish, Gadopsis marmoratus (Richardson, 1848): implications for long-term population viability. Freshwater Science 36: 113-123.

Jackson, P.D., Koehn, J.D., Lintermans, M. & Sanger, A.C. 1996. Family Gadopsidae. pp. 186-190 in McDowall, R.M. (ed.) Freshwater Fishes of South-eastern Australia. Sydney : Reed Books 247 pp.

Lake, J.S. 1971. Freshwater Fishes and Rivers of Australia. Melbourne : Nelson 61 pp.

Lake, J.S. 1978. Australian Freshwater Fishes. Melbourne : Thomas Nelson 160 pp. 140 figs.

Last, P.R., Scott, E.O.G. & Talbot, F.H. 1983. Fishes of Tasmania. Hobart : Tasmanian Fisheries Development Authority 563 pp. figs.

Lintermans, M. 2009. Fishes of the Murray-Darling Basin — An Introductory Guide. Canberra : Murray-Darling Basin Commission 157 pp. [MDBC Publication Number 10/07]

McCoy, F. 1879. Prodromus of the Zoology of Victoria. Decade 3. Melbourne : George Robertson Vol. 1 1-50 pls 21-30. (p. 39, pl. 27(2), as Gadopsis gracilis; p. 41, as Gadopsis gibbosus)

Merrick, J.R. & Schmida, G.E. 1984. Australian Freshwater Fishes Biology and Management. Sydney : J.R. Merrick 409 pp. figs 280 col. figs.

Miller, A.D., Waggy, G., Ryan, S.G. & Austin, C.M. 2004. Mitochondrial 12S rRNA sequences support the existence of a third species of freshwater blackfish (Percicthyidae: Gadopsis) from south-eastern Australia. Memoirs of Museum Victoria 61(2): 121–127 PDF available Open access

Richardson, J. 1848. Ichthyology. 75-139 pls 42-43 & 44 (parts), 45-52, 53 in Richardson, J. & Gray, J.E. (eds). The Zoology of the Voyage of H.M.S. Erebus and Terror under the Command of Captain Sir James Clark Ross, R.N., F.R.S., during the years 1839–43. London : Smith, Elder & Co. Vol. 2 139 pp.

Scott, T.D., Glover, C.J.M. & Southcott, R.V. 1974. The Marine and Freshwater Fishes of South Australia. Adelaide : Government Printer 392 pp. figs.

Steindachner, F. 1884. Ichthyologische Beiträge (13)1. Beiträge zur Kenntniss der Fische Australiens. Sitzungsberichte der Akademie der Wissenschaften in Wien. Mathematisch-Naturwissenschaftliche Klasse 88(1): 1065-1108 figs 1-8 (p. 1105, pl. 1(2), as Gadopsis fuscus).

Unmack, P.J. 2001. Biogeography of Australian freshwater fishes. Journal of Biogeography 28: 1053-1089.

Unmack, P.J., Sandoval-Castillo, J., Hammer, M.P., Adams, M., Raadik, T.A., Beheregaray, L.B. 2017. Genome-wide SNPs resolve a key conflict between sequence and allozyme data to confirm another threatened candidate species of river blackfishes (Teleostei: Percichthyidae: Gadopsis). Molecular Phylogenetics and Evolution 109: 415-420 https://doi.org/10.1016/j.ympev.2017.02.013Abstract

Quick Facts

CAAB Code:37311215


Conservation:South Australia: Protected


Max weight:60 cm; 5 kg

Native:Endemic to Australia

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CAAB distribution map